Photographic elements containing image dye-providing layer units

ABSTRACT

Photographic elements are disclosed which comprise a support having thereon at least two image dye-providing layer units wherein one of said image dye-providing layer units comprises a coarse-grain silver halide emulsion which has associated therewith a black-and-white silver halide developing agent. Processes for developing these photographic elements are also disclosed, such as contacting said photographic element with an alkaline solution containing color-developing agent and then using an amplifier solution containing a transition metal-ion complex to form image dye.

United States Patent [191 Bissonette Sept. 2, 1975 LAYER UNITS [75]Inventor: Vernon Leon Bissonette, Brockport,

[73] Assignee: Eastman Kodak Company,

Rochester, NY.

[22] Filed: Nov. 20, 1972 [21] Appl. No.: 307,893

[52] US. Cl. 96/74; 96/95; 96/100 [51] Int. Cl. G03C 1/76; 603C 1/06[58] Field of Search 96/3, 74, 95

[56] References Cited UNITED STATES PATENTS 3,192,044 6/4965 Rogers 96/33,402,046 9/1968 Zwick 96/74 3,415,646 12/1968 Land 96/3 3,591,3827/1971 Millikan 96/74 Primaiy Examiner-Norman G. Torchin AssistantExaminer.l. P. Brammer Attorney, Agent, or FirmM. R. Chipaloski [5 7]ABSTRACT Photographic elements are disclosed which comprise a supporthaving thereon at least two image dyeproviding layer units wherein oneof said image dyeproviding layer units comprises a coarse-grain silverhalide emulsion which has associated therewith a black-and-white silverhalidedeveloping agent. Processes for developing these photographicelements are also disclosed, such as contacting said photographicelement. with an alkaline solution containing colordeveloping agent andthen using an amplifier solution containing a transition metal-ioncomplex to form image dye.

23 Claims, 3 Drawing Figures OVERCOAT CYAN lMACE- DYE PROV/D/NG LAYERUN/T SPACER LAYER MACEN TA lMAGE-DYE PROV/D/NC LAYER UN/7' SPACER LAYERYELLOW /MAGEDYE PROV/D /NC LAYER UNIT 8 BLACK AND WH/TE DEVELOP/N6 AGENTSUPPOR 7' PATENTEDSEP 2191s S UPPOR 7' FIG 2 YELLOW FIG 3 OVERCOA 7'CYA/V lMAGE- DYE PROV/0W6 LAYER U/V/ T SPACER LAYER MAGENTA /MA6EDYEPROV/Dl/VG LAYER U/V/7' SPACER LA YER YELLOW lMAGE-DYE PROV/DING LAYERU/V/T 8 BLACK AND WH/TE DEVELOP/IVS AGE/VT STEPW/SE EXPOSURE DENSITY DENS/ 7 Y PHOTOGRAPI-IIC ELEMENTS CONTAINING IMAGE DYE-PROVIDING LAYERUNITS This'invcntion relates to photographic elements and processes fordeveloping image records in said photographic elements. In one aspect,this invention relates to photographic elements comprising an imagedyeproviding layer unit which comprises a light-sensitive silver halide,a stoichiometric excess of a color coupler based on effective silver anda black-and-white silver halide developing agent. In another aspect,this invention relates to multicolor photographic elements whichcomprise one image dye-providing layer unit, preferably a yellow dyeimage-providing layer unit, which comprises a silver halide emulsion,which preferably has an effective sensitivity to blue light, a colorcoupler and a black-and-white silver halide developing agent.

The use of developing agents incorporated in a photographic element,along with silver halide emulsions, whereby development can proceed byactivation with an alkaline solution is well-known in the art, forexample, as disclosed in U.S. Pat. Nos. 2,315,966 issued April 3, 1943;2,592,368 issued April 8, 1952; 2,716,059 issued Aug. 23, 1955;2,751,300 issued June 19, 1956; 3,276,871 issued Oct. 4, 1966; 3,278,307issued Oct. ll, 1966, 3,287,129 issued Nov. 22, 1960; 3,291 ,609 issuedDec. 13, 1966; and 3,342,599 issued Sept. 19, 1967.

The incorporation of black-and-white developing agents as auxiliarydevelopers in image transfer systems utilizing preformed dyes is knownin the art, for example, as disclosed in U.S. Pat. No. 3,192,044. Incertain color systems such as reversal systems, incorporatedblack-and-white developers have been used to carry out the firstdevelopment step followed by light or chemical fogging of the remainderof the undeveloped silver halide and then carrying out color developmentin the presence of a color developer such as an aromatic primary aminosilver halide developing agent and a color coupler to form dye images.In those reversal systems where the black-and-white developing agent isincorporated in the element, it is generally associated with allemulsion layers to provide contact during the first development step andall silver halide emulsion layers are generally of substantially thesame means grain size. It is also known in the art to use small amountsof black-and-white developing agents in colordeveloping compositions toact as competing developers and the like.

Several color, photographic systems used commercially are known in theprior art to utilize photographic elements containing imagedye-providing layer units which contain light-sensitive silver halideemulsions having associated therewith a color coupler. Generally,

the image dye is formed by reaction of an aromatic primary aminodeveloping agent with silver halide to oxidize the aromatic compoundwhich, in turn, reacts with the color coupler to produce an image dye.The amount of dye formed is, thus, directly dependent on the amount ofcolor-developing agent oxidized by the exposed silver halide. Therefore,black-and-white developers used in a color-coupler system would be atthe expense of dye formation if used to develop silver in the areaswhere dye formation is essential. Thus, excess stoichiometric quantitiesof developable silver halide would be necessary to obtain the same dyeformation if black-and-white developers wereused in this type of colorsystem.

l have now found that improved color photographic elements can .be madewhich generally comprise an image dye-providing layer unit containing asilver halide emulsion, a color coupler and a black-and-white silverhalide developing agent, preferably in sufficient quantity to reduce atleast 5 percent and more preferably at least 10 percent of the silverhalide to silver.

In one embodiment, the photographic elements of this invention compriseone image dye-providing layer unit which contains a coarse-grain silverhalide emulsion, a color coupler in a stoichiometric excess based onsilver halide in said layer unit, and at least one image dye-providinglayer unit which contains a black-andwhite silver halide developingagent.

In a highly preferred embodiment, multicolor photographic elements canbe made in accordance with this invention wherein one imagedye-providing layer, and preferably only one of the image dye providinglayer units, comprises a silver halide emulsion, color coupler andsufficient black-and-white developer to develop at least 5 percent ofsaid silver halide. Preferably, the multicolor element is a subtractivecolor element comprising cyan, magnenta and yellow image dye-providinglayer units and the yellow image dye-providing layer unit is the onlyunit which contains sufficient blackand-white silver halide developingagent to develop at least 5 percent of said silver halide.

In another embodiment, photographic elements are prepared according tothis invention which comprise at least two image dye-providing layerunits which contain silver halide emulsions and color coupler, saidsilver halide emulsion of at least one dye-providing layer unit having amean grain size which is 0.5 micron greater or 50 percent greater thanthe mean grain size of the silver halide emulsion of another of saidimage dye-providing layer units, wherein said image dye-providing layerunit containing the silver halide emulsion of larger mean grain size hasassociated therewith a black-and-white silver halide developing agent.

In the drawing, FIG. 1 shows a schematic diagram of one preferredphotographic element according to this invention. The yellow imagedye-providing layer unit is preferably a coarse-grain silver halideemulsion and a black-and-white silver halide developing agent is presentin said layer unit, while the magenta and cyan image dye-providing layerunits contain fine-grain, spectrally sensitized silver halide emulsionsand do not contain an incorporated silver halide developing agent.

FIG. 2 shows the sensitometric evaluation of the dyes produced with aphotographic element according to Example 1, wherein the yellow imagedye-providing layer unit contains a black-and-white developing agent,and

FIG. 3 is a sensitometric evaluation of a control element without theincorporated black-and-white incorporated developer. Furtherdetails aregiven in Example 1.

The photographic elements of this invention comprise a support havingthereon at least one image dyeproviding layer unit comprising a colorcoupler and a silver halide emulsion and at least one layer containing ablackand-white silver halide developing agent.

Preferably the image dye-providing layer unit of said element comprisesa stoiehiometric excess of color coupler based on effective ordevelopable silver halide.

Moreover, where the silver halide of the image dyeproviding layer unitis a coarse-grain silver halide emulsion, the black-and-white silverhalide developing agent is preferably contained in said unit in a mannerwhere it preferentially will start development of the coarsegrain silverhalide of said layer unit before starting development of any adjacentlayer units.

It may be helpful in understanding this invention to note that, whilethe incorporation of black-and-white developers in color photographicelements was at the expense of dye formation per unit of silver, highdye yields can be obtained in the present elements since dye formationcan proceed catalytically. Thus, the black-and-white developers can beused in systems containing high stoichiometric ratios of coupler tosilver or where the element contains both coarse-grain and fine-grainemulsions to form catalytic silver at a high rate without subsequentloss of image dye.

The term black-and-white silver halide developing agent as used hereingenerally refers to silver halide developing agents other than the colorsilver halide developing agents which enter into coupling reactions withcolor couplers to form image dyes, i.e., such as the aromatic primaryamino silver halide developing agents. The black-and-white developingagents were previously known in the art for reducing silver halide tosilver to produce an imagewise distribution of visible silver, and areto be distinguished from the colordeveloping agents which form image dyeby a secondary reaction.

The black-and-white developers may be incorporated in the photographicelements of this invention by methods disclosed in the prior art and maybe dispersed in separate colloid layers or dispersed directly in thesilver halide emulsion. Generally, the black-and-white silver halidedevelopers are present in an image dyeforming layer unit in aconcentration of from about 0. l to 200 mg./ft. and preferably from 0.5to 100 mg./ft. depending, of course, on the concentration of the silverhalide in the image dye-providing layer unit.

Useful black-and-white developing agents which can be incorporated inthe photographic elements of this invention include thoseblack-and-white developers disclosed in US. Pat. Nos. 2,315,966 by Knottissued April 6, 1943; 2,592,368 by Yackel issued April 8, 1952;2,685,510 by Yackel issued Aug. 3, 1954, 2,716,059 by Yutzy et al.issued Aug, 23, 1955, 2,751,300 by James et al. issued June 19, 1956;3,146,104 by Yackel et al. issued Aug. 25, 1964; 3,180,731 by Roman etal. issued April 27, 1965; 3,276,871 by Abbott issued Oct. 4, 1966;3,278,307 by Stewart et al. issued Oct. 1 l, 1966; 3,287,129 by Rees etal. issued Nov. 22, 1966; 3,291,609 by Porter et al. issued Dec. 13,1966; and 3,301,678 by Humphlett et al. issued Jan. 31, 1967.

In one preferred embodiment, the black-and-white developers are3-pyrazolidone silver halide developing agents. Useful developers ofthis type generally have the formula:

in which R, R R", R and R can each be a hydrogen atom, an alkyl groupcontaining from 1 to 4 carbon atoms or an aryl group preferably of thebenzene or naphthalene series and including substituted aryl groups, andR R, R and R can each additionally be an hydroxy group or anhydroxyalkyl group containing from 1 to 4 carbon atoms. Typical useful3- pyrazolidone silver halide developing agents include:

1-phenyl-3-pyrazolidone,

l-p-tolyl- 3-pyrazolidone,

5-phenyll3-pyrazolidone,

5-methyl-3-pyrazolidone,

l -pchlorophenyl-3-pyrazolidone,

l-phenyl-5 -phenyl-3-pyrazolidone l-m-tolyl-3-pyrazolidone,

1-phenyl-5-methyl'3-phyrazolidone, l-p-tolyl-5-phenyl-3-pyrazolidone,l-p-methoxyphenyl-3-pyrazolidone,

l-acetamidophenyl-3-pyrazolidone1-phenyl-2-acetyl-4,4-dimethyl-3-pyrazolidone1-phenyl-4,4-dimethy1-3-pyrazolidone,

l-m-aminophenyl-4-methyl-4-propyl-3- pyrazolidone,

1-o-chlorophenyl-4-methyl-4-ethyl-3 -pyrazolidone,

1-m-acetamidophenyl-4,4-diethyl-3-pyrazolidone,

l-( p-B-hydroxyethylphenyl )-4,4-dimethyl-3- phrazolidone,

l-p-hydroXyphenyl-4,4-dimethyl- 3-pyrazolidone,

1-p-methoxyphenyl-4,4-diethyl- 3-pyrazolidonel-p-tolyl-4,4-dimethyl-3-pyrazolidone,

1-( 7-hydroXy-2-naphtyl')-4-methyl l4-n-propyl-3- pyrazolidone,l-p-diphenyl-4,4-dimethyl-3-pyrazolidone,

1 -p-B-hydroxyethylphenyl )-3-pyrazolidone,

1-o-tolyl-3-pyrazolidone,

l-o-tolyl-4,4-dimethyl-3-pyrazolidone, 1-phenyll4-methyl-3pyrazolidone,4-hydroxy-4-methyll -phenyl-3pyrazolidone, and 4hydroxymethyl-4-methyl-1-phenyl-3-pyrazolidone.

In one preferred embodiment, the 4,4-dialkyl-3- pyrazolidone or4-alkyl-4-hydroxy-3-phyrazolidone compounds are especially useful toobtain fast development.

Other useful black-and-white developing agents include hydroquinone,catechol, pyrogallol, -N-methyl-paminophemol,p-B-hydroxyethylaminophenol, p-B- aminoethylaminophenol,N-methyl-N-(B-sulfoamidoethyl )-p-aminophenol, ascorbic acid andphydroxphenylglycine.

In certain preferred embodiments, reductones can be used such asmorpholino hexose reductone, 2,6- dimethyl morpholino hexose reductone,piperidino hexose reductone, piperidino hexose reductone monoacetate,4-methyl piperidino hexose reductone, pyrrolidino hexose reductone,dimethylamino hexose reductone, N-methylbenzylamino hexose reductone,and the like.

The photographic elements of this invention can be processed to provideimage records by several procedures.

In a highly preferred embodiment, the photographic elements can beprocessed to provide an image record by the procedures described in mycopending application, U.S. Ser. No. 189,289, entitled Image-FormingProcess and Compositions" filed Oct. 14, 1971, now abandoned andincorporated herein by reference. In

one embodiment of this process, the imagewiseexposed element iscontacted with a photographic color-developing agent and an oxidizingagent, such as a cobalt (Ill) metal complex having a coordination numberof 6, until the desired dye density is obtained. The cobalt metalcomplex is apparently reduced to cobalt (II) in the presence of silver,which appears to act as a catalyst, and the color developer is oxidizedwhereby it can react with the color coupler in each respective layerunit to form the desired image dye. The formation 7 of oxidizeddevelopercan continue as long as there is a sufficient supply of themetal complex and color developer in the presence of the silvercatalyst.

In another highly preferred process, a photographic element inaccordance with this invention is processed as disclosed by Travis, U.S.Ser. No. 256,071 entitled Process for Developing Photographic Elements,filed on May 23, 1972, now US. Pat. No. 3,765,891 this process thephotographic element in accordance with this invention which has beenimagewiseexposed is developed to convert the developable silver halideinto metallic silver and form image dye. With negative emulsions, theexposed areas will be developable, whereas with direct-positiveemulsions or reversal emulsions the unexposed areas will be developed.The photographic element containing undeveloped silver halide and animagewise distribution of metallic silver is then contacted with asuitable metal complex, such as a cobalt (lll) complex having acoordination number of 6, in the presence of a color-developing agentwhich is preferably imbibed into the element during the colordevelopmentstep and carried into the bath containing the cobalt metal complex.Preferably, the photographic element is treated with a liquid bathcontaining the suitable metal complex and which also contains a silverhalide development restrainer, thus allowing this step to proceed inroomlight. by using this process one can observe the dye formation andstop dye formation at the desired dye density.

In still another embodiment, the elements of this invention can beprocessed by using a physical developing agent such as described inDipple et al., US. Pat. No. 2,750,292 issued June 12, 1956. By treatingimagewise-exposed elements of this invention with a solution containingonly the color-developing agent and the physical developing agent,rather than the solution described by Dipple et al., it is possible toobtain a multicolor image record.

ln still another embodiment, the elements of this invention can bedeveloped by using a variation of the process described in Weber, US.Pat. No. 2,173,739. The elements of this invention which have beenimagewise-exposed can be developed, bleached partially with a solutionas described in Weber, such as a potassium ferricyanide bleach,redeveloped in color developer to intensify the image, etc., until thedesired dye density is obtained. Peroxy treatments such as used inBritish Pat. No. 1,268,126 could also be adapted in a manner similar tothe next above process for use in development of a multicolor elementaccording to this invention.

In still another embodiment, the elements of this invention can bedesigned for use in and can be processed by the color negative or colorreversal processes referred to in US. Pat. Nos. 3,046,129 by Grahamissued July 24, 1962; 3,547,640 by Beckett, and 2,944,900.

The silver halide emulsions used in accordance with this invention cancomprise, for example, silver chloride, silver bromide, silverbromoiodide, silver chlorobromide, silver chloroiodide, silverchlorobromoiodide crystals or mixtures thereof. They may be coarseorfine-grain emulsions prepared by any of the well-known techniques, e.g.,single-jet emulsions such as those described in Trivelli and Smith, ThePhotographic Journal, Vol. LXXIX, May, 1939 (pp. 330-338), double-jetemulsions such as Lippmann emulsions, ammoniacal emulsions, thiocyanateor thioether ripened emulsions such as those described in US. Pat. No.2,222,264 by Nietz et al. issued Nov. 19, 1940; 3,320,069 bylllingsworth issued May 16, 1967; and 3,271,157 by McBride issued Sept.6, 1966. Surface-image emulsions may be used or internal-image emulsionsmay be used such as those described in US Pat. Nos. 2,592,250 by Daveyet al. issued May 8', 1952; 3,206,313 by Porter et al. issued Sept. 14,1965; 3,367,778 by Berriman issued Feb. 6, 1968, and 3,447,927 by Baconet al. issued June 3, 1969. If desired, mixtures of surfaceandinternalimage emulsions may be used as described in Luckey et al, US.Pat. No. 2,996,382 issued Aug. 15, 1961. The emulsions may beregular-grain emulsions such as the type described in Klein and Moisar,J. P1101. S011, Vol. 12, No. 5, Sept,/Oct., 1964, pp. 242-251.Negative-type emulsions may be used or direct-positive emulsions may beused such as those described in US. Pat. Nos. 2,184,013 by Leermakersissued Dec. 19, 1939; 2,541,472 by Kendal et a1. issued Feb. 13, 1951;3,367,778 by Berriman issued Feb. 6, 1968; 3,501,307 by Illingsworthissued March 17, 1970; 2,563,785by lves issued Aug. 7, 1951; 2,456,953by Knott et a1. issued Dec. 21, 1948; and 2,861,885 by Land issued Nov.25, 1958; British Pat. No. 723,019 by Schouwenaars issued Feb. 2, 1955,and French Pat. No. 1,520,821 by lllingsworth issued March 4,1968.Preferably, the emulsions are negative, developing-outtype, silverhalide emulsions.

Generally, each of the color-providing layer units of the photographicelements contains a light-sensitive silver salt which is preferably asilver halide. In one preferred embodiment, at least two of thecolor-providing layer units each comprise a silver salt at aconcentration of up to 30 mg. of silver/ft? Generally, these layer unitswillbe the redand green-sensitive silver halidecontaining layer units.However, while the developable silver halide is preferably present atconcentrations based on silver of less than 30 mg./ft. it is possible tocoat blended emulsions at higher coverages within this embodiment, aslong as no more than 30 mg./ft. of silver develops; for example, suchemulsions may contain silver halide grains which are relativelylight-insensitive or may contain development restrainers, such as withdevelopment inhibitor-releasing couplers, and still provide aphotographic element which is advantageously used in the variousprocesses as described herein to produce improved image records. In someinstances, emulsions containing relatively light-insensitive grains ordevelopment inhibitors are desirable to enable one to obtain moreuniform coating coverage with less precise coating equipment, as well asfor other reasons. Thus, highly preferred photographic elements of thisinvention contain at least two color-providing layer units, eachcontaining a silver halide emulsion, defined in terms of effectivecoverage and developability as one which, when it is fully exposed andprocessed for about 1 minute at 100F. in Developer A as follows:

Color Developer A benzyl alcohol KBr hydroxylamine sulfate4-amino-N-ethyl-N-( Z-methoxyethyl )-m toluidine di-paratoluenesulfonatcethylenediaminc tetraacetic acid-sodium salt water to 1 liter pH 10.1 at24 C.

will provide less than 30 mg. of metallic silver/ft. and

preferably less than 15 mg./ft. It is understood that the term effectivesilver" refers to that amount of silver which is developed in this testand that ratios of coupler to silver are based on effective silver"which is produced by this type of development when so specified herein.In most instances, the quantity of effective silver as silver halide inthe undeveloped, unexposed photographic element will be quite similar toquantity of total silver present as silver halide. The fully exposedlayer containing silver halide emulsion is one which is exposed to Dmaxas is well-known in the art, for example, by exposure to a 500-watt,3000K lamp for about seconds (total exposure at the film plane =11.3 X10 ergs/cmf).

In certain embodiments, the emulsions of at least one imagedye-providing layer unit comprise a coarse-grain silver halide generallyhaving a mean grain size at least 0.8 micron and preferably at least 1.0micron. Grain sizes can be measured by methods commonly used in the artfor this purpose. A typical procedure is set forth by Loveland, Methodsof Particle-Size Analysis, ASTM Symposium on Light Microscopy, 1953, pp.94122, or in chapter 2 of The Theory of the Photographic Process, Meesand James, 3rd Ed. 1966), published by MacMillan Co. The grain size canbe measured using the projected areas of the grains or approximatediameter. When the grains are substantially uniform in shape, the sizedistribution can be expressed quite accurately as either diameter orprojected area. The size-frequency relationship can be determined asdisclosed in an article by Trivelli and Smith entitled EmpiricalRelations between Sensitometric and Size Frequency in PhotographicEmulsion Series, The Photographic Journal, Vol. LXXIX, 1949, pp.330-338.

The light-sensitive silver salts are generally coated in thecolor-providing layer units in the same layer with the photographiccolor coupler. However, they can be coated in separate adjacent layersas long as the coupler is effectively associated with the respectivesilver halide emulsion layer to provide for immediate dyeprovidingreactions to take place before substantial color-developer oxidationreaction products diffuse into adjacent color-providing layer units.

As used herein, the terms photographic color coupler and imagedye-providing color coupler" include and compound which reacts (orcouples) with the oxidation products of primary aromatic aminodeveloping agent on photographic development to form an image dye, andare nondiffusible in a hydrophilic colloid binder (e.g., gelatin) usefulfor photographic silver halide, and also those couplers which provideuseful image dyes when reacted with oxidized primary aromatic aminodeveloping agents such as by a coupler-release mechanism. The couplerscan form diffusible or nondiffusible dyes. Typical preferred colorcouplers include phenolic, S-pyrazolone and open-chain ketomethylenecouplers. Specific cyan, magenta and yellow color couplers which can beemployed in the practice of this invention are described in Graham etal., U.S. Pat. No. 3,046,129 issued Jan. 24, 1962, column 15, line 45,through column 18, line 51, which disclosure is incorporated herein byreference. Such color couplers can be dispersed in any convenientmanner, such as by using the solvents and the techniques described inU.S. Pat. Nos. 2,322,027 by .lelley et al. issued June 15, 1943, or2,801,171 by Fierke et al. issued July 30, 1957. When coupler solventsare employed, the most useful weight ratios of color coupler to couplersolvent range from about 1:3 to 1:0.1. The useful couplers includeFischer-type incorporated couplers such as those described in Fischer,U.S. Pat. No. 1,055,155 issued Mar. 4, 1913, and particularlynondiffusible Fischertype couplers containing branched carbon chains,e.g., those referred to in the references cited in Frohlich et al., U.S.Pat. No. 2,376,679 issued May 22, 1945, column 2, lines 5060.Particularly useful in the practice of this invention are thenondiffusible color couplers which form nondiffusible dyes.

In certain preferred embodiments, the incorporated couplers in the layerunits of this invention are waterinsoluble color couplers which areincorporated in a coupler solvent which is preferably a moderately polarsolvent. Typical useful solvents include tri-o-cresyl phosphate,di-n-butyl phthalate, diethyl lauramide, 2,4- diarylphenol, liquid dyestabilizers as described in an article entitled Improved PhotographicDye Image Stabilizer-Solvent", Product Licensing Inde.\',Vol. 83, pp.26-29, March 1971, and the like. The elements containing couplersolvents appear also to aid in imbibing color developer in thoseprocesses where it is carried from a developer bath into an amplifierbath.

The term nondiffusible used herein as applied to couplers and productsderived from couplers has the meaning commonly applied to the term incolor photography and denotes materials which for all practical purposesdo not migrate or wander through photographic hydrophilic colloidlayers, such as gelatin, particularly during processing in aqueousalkaline solutions. The same meaning is attached to the term immobile.The terms diffusible and mobile have the converse meaning.

The photographic elements of this invention, as defined above, comprisea support having thereon image dye-providing layer units. A multicolorphotographic element comprises at least two of said image dye providinglayer units which each records light primarily in different regions ofthe light spectrum. The layer unit comprises a light-sensitive silversalt, which is generally spectrally sensitized to a specific region ofthe light spectrum, and has associated therewith a photographic colorcoupler. In certain preferred embodiments, the color-providing layerunits are continuous layers which are effectively isolated from otherlayer units by barrier layers, spacer layers, layers containingscavengers for oxidized developer and the like to prevent anysubstantial color contamination between the image dyeproviding layerunits. In other embodiments, the layer units are discontinuous layerscomprising mixed packets which are effectively isolated from each other,as disclosed in Godowsky,,U.S. Pat. No. 2,698,794 issued Jan. 4, 1954.The effective isolation of the layer units is known in the art and isutilized to prevent contamination in many commercial color products.

In certain preferred embodiments, photographic elements of thisinvention comprise a support having thereon at least one imagedye-producing layer unit containing a light-sensitive silver salt,preferably silver halide, having associated therewith a stoichiometricexcess of coupler. The equivalency of color couplers is known in theart, for example, a 4-equivalent coupler requires 4 moles of oxidizedcolor developer, which in turn requires development of 4 moles ofsilver, to produce 1 mole of dye. Thus, for the stoichiometric reactionwith silver halide, l-equivalent weight of this coupler will be 0.25mole. In accordance with this embodiment, the color image-providing unitcan comprise at least a 40 percent excess of the equivalent weight ofimage dye-providing color coupler required to react on a stoichiometricbasis with the developable silver and preferably a 70 percent excess ofsaid coupler. In one highly preferred embodiment, at least a 1 percentexcess of the coupler is present in said dye imageproviding layers basedon silver. Preferably, the coupler-to-silver ratio is based on effectivesilver as defined herein. The ratio can also be defined as an equivalentexcess with a coupler-to-silver ratio of at least 1.421, and preferablyat least 1.7:1 (i.e., 2:1 being a 100 percent excess). In certainpreferred embodiments, the photographic color couplers are employed inthe image dye-providing layer units at a concentration of at least threetimes, such as from three to 20 times, the weight of the silver in thesilver halide emulsion. Weight ratios of coupler-to-silver coveragewhich are particularly useful are from 4 to parts by weight coupler to 1part by weight silver. Advantageously, the coupler is present in anamount sufficient to give a density of at least 1.7 and preferably atleast 2.0. Preferably, the difference between the maximum density andthe minimum density (which can comprise unbleached silver) is at least0.6 and preferably at least 1.0.

It is realized that the density of the dye may vary with the developingagent combined with the respective coupler, and accordingly the quantityof coupler can be adjusted to provide the desired density. Preferably,each layer unit contains at least 1 X10 moles/ft. of color coupler.

Advantageously, the photographic color couplers utilized are selected sothat they will give a good neutral dye image. Preferably, the cyan dyeformed has its major visible light absorption between about 600 and 700nm., the magenta dye has its major absorption between about 500 and 600nm., and the yellow dye has its major absorption between about 400 and500 nm.

The photographic elements of this invention are particularly useful inthe processes of the type disclosed in my copending application, Ser.No. 189,289, entitled Image-Forming Processes and Compositions, filedOct. 14, 1971 now abandoned and incorporated herein by reference.Generally, in processes of this type, a redox reaction between anoxidizing agent and a reducing agent is utilized to produce a change inlight value. This change in light value can come about directly by achange in the light value of either the oxidizing agent or reducingagent. Alternatively, the redox reaction can result in one or morereaction products which can react with each other or with anothercomponent, such as a reactive species, to produce a change in lightvalue.

In another variation, the reactivity of the reactive species can bereduced imagewise by one of the reaction products of the redox reaction.

The redox reaction which takes place when the elements are processed bythis procedure occurs at a catalytic surface. The catalyst is metallicsilver which, of course, can be produced by development of silver halidewhich contains a latent image. The catalyst appears to promote redoxreaction in true catalystic fashion. The amount of redox reactionproducts is not limited by the amount of catalytic present, since thecatalyzed redox reaction of this invention does not proceed on astoichiometric basis with respect to the catalyst.

Oxidants preferred in the practice of this process are the metalcomplexes, such as a transition metal complex, e.g., a Group VIII metalcomplex, or a complex of a metal of Series 4 of the periodic tableappearing on pp. 54 and 55 of Langes Handbook of Chemistry, 8th Edition,published by Handbook Publisher, Inc., Sandusky, Ohio, 2. Such complexesfeature a molecule having a metallic atom or ion. This metallic atom orion is surrounded by a group of atoms, ions or other molecules which aregenerically referred to as liquids. The metallic atom or ion in thecenter of these complexes is a Lewis acid; the ligands are Lewis bases.Werner complexes are well-known examples of such complexes. The usefulmetal salts are typically capable of existing in at least two valentstates. In a preferred aspect of the invention, the metal complexes arethose referred to by American chemists as inert and by European chemistsas robust". Particularly useful are complexes of a metal ion with aligand which, when a test sample thereof is dissolved at 0.1 molarconcentration at 20C. in an inert solvent solution also containing 0.1molar concentrationn of a tagged ligand of the same species which isuncoordinated, exhibits essentially no exchange of uncoordinated andcoordinated ligands for at least 1 minute, or more. This test isadvantageously conducted under the pH conditions which will be utilzedin the practice of the invention. In silver halide photography, thisgenerally will be a pH of over about 8. Many metal complexes useful inthis invention show essentially no exchange of uncoordinated andcoordinated ligands for several days. The definition of inert metalcomplexes and the method of measuring ligand exchange using radioactiveisotopes to tag ligands are well-knownn in the art; see, for example,Taube, Chem. Rev., Vol. 50, p. 69 (1952), and Basolo and Pearson,Mechanisms of Inorganic Reactions, a Study of Metal Complexes andSolutions, 2nd Edition, 1967, published by John Wiley and Sons, p. 141.Further details on measurement of ligand exchange appear in articles byAdamson et al., J. Am. Chem. Soc, Vol., 73, p. 4789 (1951). The inertmetal complexes should be contrasted with labile complexes which, whentested by the method described above, have a reaction halflife generallyless than 1 minute. Metal chelates are a special type of metal complexin which the same ligand (or molecule) is attached to the central metalion at two or more different points. The metal chelates generallyexhibit somewhat slower ligand exchange than nonchelated complexes.Labile-type chelates may have a half-life of several seconds, or perhapsslightly longer. Generally, the oxidizing agents employed are notreduced to a zero valent metal during the redox reaction. Preferredmetal complexes in accordance with this process have coordinationnumbers of 6 and are known as octahedral complexes. Cobalt complexes areespecially useful in the practice of this invention. Most square planarcomplexes (which have a coordination number of 4) are rather labile,although some Group VIII metal square planar complexes, particularlyplatinum and palladium square planar complexes, exhibit inertness torapid ligand exchange.

A wide variety of ligands can be used with a metal ion to form suitablemetal complexes. Nearly all Lewis bases (i.e., substances having anunshared pair of electrons) can be ligands in metal complexes. Sometypical useful ligands include the halides, e.g., chloride, bromide,fluoride, nitrite, water, amino, etc., as well as such common ligands asthose referred to on p. 44 of Basolo el al., supra. The lability of acomplex is influenced by the'nature of the ligands selected in formingsaid complex.

Particularly useful cobalt complexes have a coordination number of 6 andhave a ligand selected from the group consisting of ethylenediamine(en),diethylenetriamine( dien triethylenetetraamine(trien ammine(NH;,),nitrate, nitrite, azide, chloride, thiocyanate, isothiocyanate, water,carbonate, and propylenediamine(tn). The preferred cobalt complexescomprise l at least 2 ethylenediamine ligands or 2) at least 5 ammineligands or 3) l triethylenetriaamine ligand. Especially useful are thecobalt hexammine salts (e.g., the chloride, bromide, sulfite, sulfate,perchlorate, nitrite and acetate salts). Some other specific highlyuseful cobalt complexes include those having one of the followingformulas: [Co(NH;,) -,H O]X; [C( :;)5 s] :i)s [C0(NH3)* 4 3l l )3] )2(3)2] trans- )2( )2] ).1l l n)]X; n [Co( tn)(en ]X', wherein X representsone or more anions determined by the charge neutralization rule.Complexes containing oxidized noble metals or ferromagnetic metals, suchas complexes of Cr', Fe, Rh', Pt, Pd and Ir', which have reactivitiessimilar to the complexes listed above, could be used in the practice ofthis invention. The redox equilibra published in Stabilitv Constants 0fMetal-Ion Complexes, Sillen and Martel], published by The ChemicalSociety, Burlington House, London, England (1964), indicate that othercomplexes have reactivities generally similar to the cobalt complexesmentioned above.

With many complexes, such as cobalt hexammine, the anions selected cansubstantially effect the reducibility of the complex. The following ionsare listed in the order of those which give increasing stability tocobalt hexammine complexes: bromide, chloride, nitrite, perchlorate,acetate, carbonate, sulfite, and sulfate. Other ions will also effectthe reducibility of the complex. These ions should, therefore, be chosento provide complexes exhibiting the desired degree of reducibility. Someother useful anions include chloride, nitrate, thiocyanate, dithionateand hydroxide. Neutral complexes such as [Co(dien)(SCN)- OH], areuseful, but positively charged complexes are generally preferred.

Numerous reducing agents can be utilized in carrying out the sameprocess. The reducing agents utilized herein undergo redox reaction withthe oxidizing agent at a catalytic surface. In certain aspects, thereducing 12 agent used in this process is an aromatic primary aminecolor-developing agent such as p-aminophenols or pphenylenediamines.Color-developing agents which can be used include3-acetamido-4-amino-N,N-

diethylaniline, 4-amino-N-ethyl-N-B- hydroxyethylaniline sulfate,N,N-diethyl-pphenylenediamine, 2-amino-5 -diethylaminotoluene,

N-ethyl-N-B-methanesulfonamidoethyl-3-methyl-4- aminoaniline,4-amino-N-ethyl-3-methyl-N-9B-sulfoetyl)ani1ine, and the like. See Bentet al., JACS, Vol. 73, pp. 3lOO3l25 (1951), and Mees and James, TheTheory of the Photographic Process, 3rd Edition, 1966, published byMacMillan Co., New York, pp. 278-31 1, for further typical, usefuldeveloping agents.

In one highly preferred embodiment, aromatic primary aminocolor-developing agents which provide good results in this process are4-amino-N,N- diethylaniline hydrochloride, 4-amino-3-methyl-N,N-diethylaniline hydrochloride, 4-amino-3-methyl-N- ethyl-N-B-(methanesulfonamido )ethylaniline sulfate hydrate,4-amino-3-methyl-N-ethyl-N-B- hydroxyethylaniline sulfate,4-amino-3-dimethylamino- N,N-diethylaniline sulfate hdyrate, 4-amino-3-methoxy-N-ethyl-N-B-hydroxyethylaniline hydrochloride,4-amino-3-B-(methanesulfonamido)ethyl-N,N- diethylanilinedihydrochloride and 4-amino-N-ethyl-N- (Z-methoxyethyl)-m-toluidinedi-p-toluene sulfonate.

The invention can be further illustrated by the following examples.

EXAMPLE 1 A multilayer photographic element is prepared by coating thefollowing layers in order with the ingredient being listed in mg./ft.

1. paper support;

2. layer containing blue-sensitive silver halide emulsion (1.2 micronsmean grain size) at 16 mg./ft. based on silver, gelatin at 122, theyellow image dye-providing coupler a-pivalyl-4-( 4-benzyloxyphenylsulfonyl )phenoxy-Z-ehloro-S I-2,4-di-tert-amylphenoxy)butyramido1aeetanilide at 60, coupler solventdi-n-butyl phthalate at 15, and 4-hydroxymethyl-4-methyll -phenyl-3-pyrazolidone at 2;

3. layer combining gelatin at and the scavenger for oxidized developerdi-tert-octyl hydroquinone at 5;

4. layer containing a green-sensitive silver halide emulsion (0.3 micronmean grain size) at 10 mg./ft. based on silver, gelatin at 132, themagenta image dye-providing color coupler l(2,4,6- trichlorophenyl)-3-{5 a-( 3-tert-butyl-4- hydroxyphenoxy)tetradecanamido1-2-chloroaniliano 5-pyrazolone at 25, and the coupler solvent tri-cresylphosphate at 12.5;

5. layer containing gelatin at and di-tert-octyl hydroquinone at 4.5;

6. layer containing a red-sensitive silver halide emulsion (0.3 micronmean grain size) at 6 mg./ft. based on silver, gelatin at 90, the cyandye imageproviding coupler 2-[ oz-( 2.4-di-tertamylphenoxy)butyramido]-4,6-dichloro-5- methylphenol at 35,and di-n-butyl phthalate at 17.5;

7. layer containing gelatin at 100.

The phototgraphic element is exposed through a graduated-density testobject and processed in the following sequence:

color-develop 0.5 min. (40 C.) amplify 1.5 min. (40 C.) bleach-fix lmin. (40 C.) wash 1.5 min. (26 C.) dry The processing baths have thefollowing composition:

Color Developer benzyl alcohol 15 ml. K. .s0. 4 KBr 0.4 g. hydroxylaminesulfate 2 g. 4-amino-N-ethyl-N-(Z-methoxyethyl)-m- 7.5 g.

toluidine di-paratoluenesulfonate K. ,CO;, 30 g. diaminopropanoltetraacetic acid 5 g. water to 1 liter; pH l0.l

Amplifier benzyl alcohol .5 ml. [Co(NH;,)6]Cl:, 10 g. KBr 2 g. K. -CO;,7.5 g. K 50 2.0 g. diaminopropanol tetraacctic acid 10.0 g. water to lliter; pH l0.l

Bleach-Fix diaminopropanol tctraacetic acid 3 g. acetic acid ml. (10%(NH,,) S O;, l50 ml. N21 50:, l5 g. [Co(NH;,)6|Cl:, 3 g.

water to 1 liter; pH 4.5

The processed sample is sensitometrically evaluated by recording the Hand D curves of the developed yellow, magenta and cyan dye images. Thecurves are illustrated in FIG. 2.

The process is repeated with a control sample where4-hydroxymethyl-4-methyll -phenyl-3-pyrazolidone has been omitted fromthe blue-sensitive, silver halide emulsion layer. The H and D curves forthe processed sample are shown in FIG. 3.

A comparison between the two sets of H and D curves shows the beneficialeffect of the incorporated developing agent on the development of theyellow dye image in the initially blue-sensitive, silver halide emulsionlayer.

Yellow contrast is increased due to increased developability of thecoarse-grained emulsion. There is a very small speed increase in theother two layers, but no significant change in curve shape. Only theyellow dye image is improved substantially.

EXAMPLE 2 Results similar to those described in Example 1 are producedwith separate coatings wherein the bluesensitive, silver halide emulsionlayer contains 1) 2 mg./ft. of l-phenyl-4,4-dimethyl-3-pyrazolidone, 2)l0 mg./ft. of 1-phenyl-4,4-dimethyl-3pyrazolidone, 3) l0 trig/ft. of4-hydroxymethyl-4-methyll -phenyl-3- pyrazolidone, and 4) 50 mg./ft. ofpiperidino hexose reductone.

EXAMPLE 3 A prolongation of the development time in the proceduredescribed in Example 1 for the control sample from 30 seconds to 1minute provides an increase in yellow-dye density. It appears that thedevelopment time in the color developer must be doubled for this elementwhich does not contain incorporated black-andwhite developer in order toachieve a substantial match of the yellow-dye image H and D curve withthe cyan and magenta H and D curves.

Although the inventionhas been described in considerable detail withparticular reference to certain preferred embodiments thereof.variations and modifications can be effected within the spirit and scopeof the invention.

1 claim:

1. An unexposed photographic element comprising a support having thereonat least two image dyeproviding layer units, each containing a silverhalide emulsion having associated therewith a color coupler, wherein oneof said image dye-providing layer units contains a coarse-grain silverhalide emulsion which has a mean grain size which is at least 50 percentgreater than the mean grain size of said silver halide emulsion in saidother image dye-providing layer unit. said photographic elementcontaining a black-andwhite silver halide developing agent associatedwith the image dye-providing layer unit containing said coarsegrainsilver halide emulsion.

2. A photographic element according to claim 1 wherein said colorcoupler of said image dye-providing layer unit containing saidcoarse-grain silver halide emulsion is a yellow image dye-producingcolor coupler.

3. A photographic element according to claim 1 wherein said imagedye-providing layer unit contains said black-and-white developing agentin a concentration of from about 0.1 to about 200 mg./ft.".

4. A photographic element according to claim 1 wherein saidblack-and-white developing agent is a 3- pyrazolidone silver halidedeveloping agent.

5. A photographic element according to claim 1 wherein said coarse-grainsilver halide emulsion has a mean grain size of at least 0.8 micron.

6. A photographic element according to claim 1 wherein said imagedye-providing layer units are separated by an interlayer.

7. A photographic element according to claim 1 wherein said colorcoupler of said image dye-providing layer unit containing saidcoarse-grain emulsion in a yellow image dye-providing color coupler andsaid element contains two additional image dye-providing layer unitswhich each contain a silver halide emulsion having a main grain sizewhich is less than half the mean grain size of said coarse-grain silverhalide emulsion and a cyan image dye-providing color coupler or amagenta image dye-providing color coupler.

8. A photographic element according to claim 1 wherein at least one ofsaid image dye-providing layer units contains less than 30 mg./ft. ofsilver halide based on silver coverage.

9. A photographic element according to claim 1 wherein said imagedye-providing layer unit which contains the smaller means-grain-sizesilver halide emulsion also contains said color coupler in astoichiometric excess based on silver halide.

10. A photographic element according to claim 9 wherein said imagedye-providing layer unit contains said color coupler in at least a 40percent stoichiometric excess based on silver halide.

11. An unexposed multicolor photographic element comprising a supporthaving thereon an image dyeproviding layer unit containing a fine-grainsilver halide emulsion and a color coupler in a stoichiometric excessbased on said silver halide and an image dye-providing layer unitcontaining a coarse-grain silver halide emulsion having a mean grainsize at least 50 percent larger than said fine-grain silver halideemulsion, a color coupler, and a black-and-white silver halidedeveloping agent.

12. A photographic element according to claim 1 wherein the colorcoupler of said image dye-providing layer unit containing saidfine-grain emulsion is a cyan or magenta image dye-providing layer unitand said color coupler of said image dye-providing layer unit containingsaid coarse-grain emulsion is a yellow image dye-providing coupler.

13. An unexposed photographic element comprising a support and at leastone image dye-providing layer thereon containing a silver halideemulsion having a mean grain size of at least 0.8 micron, a colorcoupler, and a black-and-white silver halide developing agent at aconcentration of about 0.1 to 200 mg./ft.

14. A photographic element according to claim 13 wherein saidblack-and-white silver halide developing agent is a S-pyrazolidone.

15. A photographic element according to claim 13 wherein said co'lorcoupler is present in at least a 40 percent stoichiometric excess basedon silver in said layer unit.

16. An unexposed photographic element comprising a support havingthereon 1) an image dye-providing layer unit containing a blue-sensitivesilver halide emulsion having a mean grain size of at least 0.8 micronand having associated therewith a yellow image dyeforming coupler andfrom 0.1 to 200 mg./ft, of a blackand-white silver halide developingagent, 2) an image dye-providing layer unit containing a green-sensitivesilver halide emulsion having associated therewith a magenta imagedye-forming color coupler and 3) an image dye-providing layer unitcontaining a redsensitive silver halide having associated therewith acyan image dye-forming color coupler.

17. A photographic element according to claim 16 wherein said cyan andmagenta image dye-forming color coplers are present in said imagedye-providing layer units in at least a 40 percent stoichiometric excessbased on silver.

. 18. A photographic element according to claim 17 wherein said imagedye-providing layer units containing said green-sensitive silver halideemulsion and said red-sensitive silver halide emulsion each contain lessthan 30 mg./ft. of silver halide based on silver.

19. A photographic element according to claim 16 wherein saidblue-sensitive silver halide emulsion has a mean grain size which is atleast 50 percent greater than the mean grain size of said greenorred-sensitive silver halide emulsions.

20. A photographic element according to claim 16 wherein saidblack-and-white developing agent is a 3- pyrazolidone.

21. A photographic element according to claim 16 wherein said imagedye-providing layer units which contain said redand green-sensitivesilver halide emulsions are substantially free of black-and-white silverhalide developing agent.

22. A photographic element according to claim 16 wherein saidblaek-and-white developing agent is a 4,4-diethyl-3-pyrazolidone or a4-alkyl-4-hydroxy-3- pyrazolidone.

23. A photographic element according to claim 16 wherein said supporthas thereon the image dyeproviding layers in sequence with the imagedyeproviding layer containing the yellow dye-forming coupler nearer saidsupport UNITED STATES PATENT OFFICE G CERTIFICATE OF CORRECTICN PatentNo. 5, 902,9 5 Dated September 975 l Vernon Leon Bissonette It iscertified that error appears in the above-identified patent and thatsaid Letters Patent are hereby corrected as shown below:

Column 2, line 25, magnenca should read "magenta".

Column L, line ll, 5--phen;yll3pyrazolidi ne should read5-phenyl3pyrazolidone.

Column line 16, E-phyrazolidone should read -3-pyrazolidone--.

. Column L, line 27, "phrazolidone" should read -pyrazolidone.

Column L, line 31, L-methyllL -n-" should read 4-methyl-fl-n- Column L,line 37, l-phenyllflshould read l-phenyl-M- Column A, line #1,"3-phyrazolidone" should read --3-pyrazolidone--.

Column L, line 46, "aminophemol" should read aminophenol.

Column 5, line 18, after 3,765,891" insert I Column 7, line 61, 'and"should read -any.

Column 9, line 6, producing" should read -providing-.

Column 10, line 23, "liquids" should read ligands-.

Column 10, line 35, concentrationn should read 0 --concentrat1on-.

FORM F'0-1050 (10-69) USCOMM-DC 60376-Pl0 U.5. GOVERNMENT PRINTINGOFFICE: 8 9 I 9 o Inventor(s) Vernon Leon Bissonette Patent No 3 a 9 5Dated September 2, 1975 It is certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

Column 10, line 38, after "minute,"

insert and preferably for at least several hours, such as up to 5 hours.

Column 10, line Column 12, line N-B-sulfo- Column 12, line Column ColumnColumn Column [SEAL] line line

line

line

U7, "Knownn" should read 1 :nown--.

9, "-N-9B-sulfo" should read 7, "coplers" should read "couplers",

Signed and Sealed this twentieth D of January 1976 A ttest:

RUTH C. MASON Arresting Officer C. MARSHALL DANN Commissioner oflarentsand Trademarks

1. AN UNEXPOSED PHOTOGRAPHIC ELEMENT COMPRISING A SUPPORT HAVING THEREONAT LEAST TWO IMAGE DYE-PROVIDING LAYER UNITS, EACH CONTAINING A SILVERHALIDE EMULSION HAVING ASSOCIATED THEREWITH A COLOR COUPLER, WHEREIN ONEOF SAID IMAGE DYE-PROVIDING LAYER UNITS CONTAINS A COARSE-GRAIN SILVERHALIDE EMULSION WHICH HAS A MEAN GRAIN SIZE WHICH IS AT LEAST 50 PERCENTGREATER THAN THE MEAN GRAIN SIZE OF SAID SILVER HALIDE EMULSION IN SAIDOTHER IMAGE DYE-PROVIDING LAYER UNIT, SAID PHOTOGTAPHIC ELEMENTCONTAINING A BLACK-AND-WHITE SILVER HALIDE DEVELOPING AGENT ASSOCIATEDWITH THE IMAGE DYE-PROVIDING LAYER UNIT CONTAINING SAID COARSE-GRAINSILIVER HALDE EMULSION.
 2. A photographic element according to claim 1wherein said color coupler of said image dye-providing layer unitcontaining said coarse-grain silver halide emulsion is a yellow imagedye-producing color coupler.
 3. A photographic element according toclaim 1 wherein said image dye-providing layer unit contains saidblack-and-white developing agent in a concentration of from about 0.1 toabout 200 mg./ft.2.
 4. A photographic element according to claim 1wherein said black-and-white developing agent is a 3-pyrazolidone silverhalide developing agent.
 5. A photographic element according to claim 1wherein said coarse-grain silver halide emulsion has a mean grain sizeof at least 0.8 micron.
 6. A photographic element according to claim 1wherein said image dye-providing layer units are separated by aninterlayer.
 7. A photographic element according to claim 1 wherein saidcolor coupler of said image dye-providing layer unit containing saidcoarse-grain emulsion in a yellow image dye-providing color coupler andsaid element contains two additional image dye-providing layer unitswhich each contain a silver halide emulsion having a main grain sizewhich is less than half the mean grain size of said coarse-grain silverhalide emulsion and a cyan image dye-providing color coupler or amagenta image dye-providing color coupler.
 8. A photographic elementaccording to claim 1 wherein at least one of said image dye-providinglayer units contains less than 30 mg./ft.2 of silver halide based onsilver coverage.
 9. A photographic element according to claim 1 whereinsaid image dye-providing layer unit which contains the smallermeans-grain-size silver halide emulsion also contains said color couplerin a stoichiometric excess based on silver halide.
 10. A photographicelement according to claim 9 wherein said image dye-providing layer unitcontains said color coupler in at least a 40 percent stoichiometricexcess based on silver halide.
 11. An unexposed multicolor photographicelement comprising a support having thereon an image dye-providing layerunit containing a fine-grain silver halide emulsion and a color couplerin a stoichiometric excess based on said silver halide and an imagedye-providing layer unit containing a coarse-grain silver halideemulsion having a mean grain size at least 50 percent larger than saidfine-grain silver halide emulsion, a color coupler, and ablack-and-white silver halide developing agent.
 12. A photographicelement according to claim 1 wherein the color coupler of said imagedye-providing layer unit containing said fine-grain emulsion is a cyanor magenta image dye-providing layer unit and said color coupler of saidimage dye-providing layer unit containing said coarse-grain emulsion isa yellow image dye-providing coupler.
 13. An unexposed photographicelement comprising a support and at least one image dye-providing layerthereon containing a silver halide emulsion having a mean grain size ofat least 0.8 micron, a color coupler, and a black-and-white silverhalide developing agent at a concentration of about 0.1 to 200 mg./ft.2.14. A photographic element according to claim 13 wherein saidblack-and-white silver halide developing agent is a 3-pyrazolidone. 15.A photographic element according to claim 13 wherein said color coupleris present in at least a 40 percent stoichiometric excess based onsilver in said layer unit.
 16. An unexposed photographic elementcomprising a support having thereon 1) an image dye-providing layer unitcontaining a blue-sensitive silver halide emulsion having a mean grainsize of at least 0.8 micron and having associated therewith a yellowimage dye-forming coupler and from 0.1 to 200 mg./ft.2 of ablack-and-white silver halide developing agent, 2) an imagedye-providing layer unit containing a green-sensitive silver halideemulsion having associated therewith a magenta image dye-forming colorcoupler and 3) an image dye-providing layer unit containing ared-sensitive silver halide having associated therewith a cyan imagedye-forming color coupler.
 17. A photographic element according to claim16 wherein said cyan and magenta image dye-forming color coplers arepresent in said image dye-providing layer units in at least a 40 percentstoichiometric excess based on silver.
 18. A photographic elementaccording to claim 17 wherein said image dye-providing layer unitscontaining said green-sensitive silver halide emulsion and saidred-sensitive silver halide emulsion each contain less than 30 mg./ft.2of silver halide based on silver.
 19. A photographic element accordingto claim 16 wherein said blue-sensitive silver halide emulsion has amean grain size which is at least 50 percent greater than the mean grainsize of said green- or red-sensitive silver halide emulsions.
 20. Aphotographic element according to claim 16 wherein said black-and-whitedeveloping agent is a 3-pyrazolidone.
 21. A photographic elementaccording to claim 16 wherein said image dye-providing layer units whichcontain said red- and green-sensitive silver halide emulsions aresubstantially free of black-and-white silver halide developing agent.22. A photographic element according to claim 16 wherein saidblack-and-white developing agent is a 4,4-diethyl-3-pyrazolidone or a4-alkyl-4-hydroxy-3-pyrazolidone.
 23. A photographic element accordingto claim 16 wherein said support has thereon the image dye-providinglayers in sequence with the image dye-providing layer containing theyellow dye-forming coupler nearer said support.